The omission of an estimated $4.1 million in assessments on Montgomery County real estate tax bills to fund the Miami Conservancy District is being blamed on a clerical error.

More than 18,000 property owners in Montgomery County are charged the annual assessment to fund the Conservancy Distinct’s flood protection program, Auditor Karl Keith said.

The assessments were left off first-half year property tax bills that were mailed in January.

“It was an innocent mistake,” Keith said. “The clerk who oversees the charges discovered the error.”

The auditor said he has mailed adjusted bills to 100 property owners whose assessment exceeded $3,000. The total charge on those bills was $2.4 million. The adjusted bills are due March 1. If they are paid late, Keith said no penalty will be assessed.

The error means the conservancy district will experience a three to four month delay in getting the funds, Keith said. Officials of the conservancy district could not be reached for comment Thursday.

The city of Dayton will get the largest adjusted bill at $951,981, followed by the Montgomery County Board of Commissioners at $418,595.

“We would have had to pay it anyway,” County Commission President Dan Foley said. “It was an oversight. As soon as the auditor realized it, he notified key parties. He did the right thing.”

Other notable property owners getting adjusted bills include Children’s Medical Center, the University of Dayton and CareSource Management.

The average bill for the 12,858 residential property owners who are assessed the charge is $56.68. For those property owners, the adjustment will be made on the second half of the year real estate tax bills, which will be mailed in June and are due in July.

Property owners with questions regarding these charges or adjusted tax bills should contact the Montgomery County Auditor’s Office at 937-225-4326.

The annual Miami Conservancy flood protection assessment dates back to the 1920s and is levied to fund on-going maintenance of the region’s flood protection system. Additionally, the district’s Dam Safety Initiative funds capital improvement projects on dams and levees in the Miami Conservancy District.